The present invention relates to the preparation of aminotriazines which are useful in the production of commercial herbicides.
U.S. Pat. No. 2,418,476 of Nagy et al. discloses the synthesis of zinc bis(dicyanimide) Zn[N(CN).sub.2 ].sub.2. This insoluble compound can be converted to a coordination complex, zinc bis(imino-bis-carbimic acid methyl ester) by refluxing in methanol, disclosed in Rembarz et al., J. fur Pract. Chemie 1969 (311) 889-892. This reaction produces the coordination complex in a yield of about 50% to 75% along with some insoluble materials. The coordination complex is then converted to 2-methyl-4,6-dimethoxy-1,3,5-triazine.
East German Pat. Nos. 70,296 of Rembarz et al. and 71,768 of Rober et al., Great Britain Patent No. 1,180,346 of Rober et al., and Rembarz et al., Wiss. Z. Univ. Rostock. Math.-Naturwiss. Reihe, 1972, 21(2) 93-100 each discloses similar transformations of zinc bis(dicyanimide) to zinc bis(imino-bis-carbimic acid methyl ester) to 2-methyl-4,6-dimethoxy-1,3,5-triazine.
Kohler, Z. Anorg. Allg. Chemie., 331 (5-6), 237, (1964) discloses the preparation of metal bis(dicyanimide)bis(pyridine), M[N(CN).sub.2 ].sub.2 (pyridine)2, by reacting sodium dicyanimide with salts of bivalent transition metals in the presence of pyridine.
G.B. No. 1,067,695 of Tsujikawa and Rembarz et al. Wiss. Z. Univ. Rostock, Math.-Naturwiss. Reihe, 1972, 21(2), 113-117 each discloses the conversion of 2-methyl-4,6-dimethoxy-1,3,5-triazine to 2-methyl-4-methoxy-6-methylamino-1,3,5-triazine.
The major problem encountered in the known reactions is the relatively moderate yield of the coordination complex, zinc bis(imino-bis-carbimic acid methyl ester), and the difficulty in its isolation due to the insolubles present. This limits the yield of aminotriazines obtainable. The Kohler pyridine complex is obtainable in high yields, but its use in the preparation of aminotriazines is not disclosed or suggested.
It has now been found that several novel ligand complexes as well as the metal bis(dicyanimide)bis(pyridine) complex of Kohler can be used in a high yield conversion of metal bis(dicyanimide) to a metal bis(imino-bis-carbimic acid methyl ester) complex. This permits efficient preparation of aminotriazines for use in herbicide production. None of the above cited references disclose the novel metal.dicyanimide.ligand complexes or their use in the quantitative preparation of the metal bis(imino-bis-carbimic acid methyl ester) complex.